To remove water from the patient, as is generally necessary, other solutes may be added to generate the necessary osmotic pressure. Typically, this solute is a sugar such as glucose, which may normally be present in peritoneal dialysis solutions in a concentration of at 0.5 to 4.25 percent (wt/vol.). When it is desired to increase the ultrafiltration of water from the patient, higher concentrations of sugar in that range are used.
However, as a disadvantage of this system for inducing ultrafiltration, during the peritoneal dialysis procedure, as water diffuses into the peritoneal dialysis solution, sugar present in the peritoneal dialysis solution diffuses into the bloodstream to a significant extent. Accordingly, while the system is safe and effective for increasing the ultrafiltration during peritoneal dialysis, the patient receives a heavy dose of calories during each peritoneal dialysis procedure from the sugar diffusing into his bloodstream. In many instances, this high caloric dose is undesired, as it can result in weight gain and fat. Particularly in the case of diabetics, the transport of significant quantities of a sugar such as glucose or fructose from the peritoneal dialysis solution into the patient's bloodstream can create complications in the medical maintenance of the patient.
Glycerol, which is a sugar alcohol, has been added on an experimental basis to glucose-containing hemodialysis solution in which the dialysis solution is directly dialyzed with an artificial membrane against blood. See the articles by Arieff et al., Kidney International, Volume 14 (1978) pages 270-278, and Van Stone et al., Transactions of the Americal Society for Artificial Internal Organs, Volume 25 (1979) pages 354-356. The purpose of such addition of glycerol was in an attempt to reduce the incidence of "disequilibrium syndrome", which is believed to result from the reduction of plasma osmolality relative to the osmolality of cell interiors due to the hemodialysis procedure. According to the latter article, the presence of glycerol was unsuccessful in reducing the symptoms of disequilibrium syndrome.
Also, the polyalcohol sorbitol has been used in peritoneal dialysis solutions. However, sorbitol proved to be toxic under certain conditions of chronic use, due to the creation of a hyperosmolar state, which naturally severely limited its utility.